I. Field of the Invention
Embodiments of the present invention relate generally to intravascular devices for treating certain medical conditions. In particular, embodiments are directed to devices for occluding an abnormal opening in a patient's body, such as a septal defect.
II. Description of the Related Art
Over the past few decades, advances have been made in the diagnosis and treatment of septal defects, such as atrial septal defects and ventricular septal defects. In general, septal defects are congenital heart defects in which the inner wall separating the left and right sides of the heart (i.e., the septum) has a hole or an opening that has failed to close.
FIGS. 1A and 1B show schematic representations of a patient's heart 5. In FIG. 1A, the patient's heart 5 has a hole 10 in the septum 15 between the heart's two upper chambers (the left atrium 20 and the right atrium 25), called an atrial septal defect (ASD). In FIG. 1B, the patient's heart 5 has a hole 10 in the septum 15 between the heart's two lower chambers (the left ventricle 30 and the right ventricle 35), called a ventricular septal defect (VSD). Ventricular septal defects can occur in any location of the ventricular septum. Two common locations for these defects are the perimembranous septum and the muscular septum.
As a result of an atrial septal defect or a ventricular septal defect, blood is able to pass from the left side of the heart to the right side, mixing oxygen-rich blood with oxygen-poor blood. This can cause a variety of problems for the individual as time goes on, such as pulmonary hypertension, right-sided heart failure, atrial fibrillation or flutter, and stroke.
One way to non-surgically treat septal defects is to permanently place an occluding device in the heart to cover the hole. The occluding device is typically delivered to the site of the septal defect using a catheter, which is inserted into the blood vessel in the patient's groin and passed through vessels into the heart's chambers. At the site of the defect, the occluding device may be deployed from the catheter and permanently placed in the hole. With time, the lining of the heart wall should grow over the device to seal the hole completely.
The configuration of the particular occluding device used to repair the defect may depend on the size and location of the defect. For example, the force needed to retain the device within the defect typically increases as the size of the defect increases. In addition, the location of the septal defect with respect to adjacent heart structures may also be taken into consideration. For example, in a membranous type ventricular septal defect, it may be difficult to effectively position a prior art occluding device without at least partially interfering with the functioning of valves such as the aortic valve 40 and/or the tricuspid valve 41 (shown in FIGS. 1A and 1B), causing valve regurgitation or some other valve malfunction.
Accordingly, there is a need for an improved occluding device that is easily delivered to the defect site, can be accurately placed at the defect site, resists dislodgement, conforms to the patient's anatomy, does not interfere with adjacent heart structures or heart conduction pathways, and overcomes the shortcomings of conventional solutions.